It is well known that combustion in diesel engines results in emissions which pollute the air. These emissions include particulates such as soot. In 1991, new government standards which require that particulate emissions from diesel engines be substantially reduced will come into effect. Present efforts to reduce emissions from diesel engines include re-designing engines and modifying combustion processes to decrease formation of polluting particulates. However, these modifications alone still cannot reduce particulate emissions to the 1991 required limits without the use of exhaust treatment systems.
Present exhaust treatment systems employ various types of filtering elements inserted in the exhaust pipeline. Under normal driving conditions, however, the exhaust gas backpressure increases due to the accumulation of the particulate matter in the filtering element. As a result of this increased backpressure, fuel consumption increases and drivablility deteriorates. Present solutions to this problem include complicated systems for regenerating the filter element by burning the particulates off of the filtering element. Such regeneration requires the use of high temperatures which ultimately cause the filtering element to deteriorate from melting and cracking.